SE-C 189584 (Grubbens & Co) describes a known pulper of the aforesaid kind.
U.S. Pat. No. 4,607,802 (Lamort) describes a similar pulper where the rotor shaft carries helical vanes that extend radially from the attachment part of said shaft.
EP-A2 0117716 (The Black Clawson company) describes a pulper in which the end of the rotor has a conically narrowing part at the attachment part of said rotor.
DE-C 3 149 135 (Sulzer-Escher-Wyss) describes a pulper whose rotor has outwardly projecting arms that move along the screening plate so as to keep the plate clean.
GB-A 2 113 570 (Beloit) describes a pulper whose rotor is provided with detachable defibration plates that move over a screening plate.